Firms need to submit their bids for the work by June 6 to Al-Khafji Joint Operations Co (KJO), industry sources said.

Three sources said the project would cost around $500 million while a fourth source pegged it at $900 million.

KJO was set up by Aramco Gulf Operations, a subsidiary of state oil firm Saudi Aramco and Kuwait Gulf Oil Co (KGOC).

The two share the Al-Khafji, Lulu, Hout and Dorra fields, which are located in the Neutral Zone between Saudi Arabia and Kuwait.

The winning firm would build offshore gas gathering facilities, pipelines and onshore gas facilities, sources said.

The project would help recover the associated gas, which is now being flared.

International firms have the option to submit a combined proposal which would help reduce the cost of the project, one of the sources said.

“The key to success is to provide a combined proposal,” said one source.

Khafji, located in the Neutral Zone between Kuwait and Saudi Arabia, has an oil capacity of around 610,000 barrels per day.

Most of the gas produced by both countries is a by-product of oil output, so when they pump less crude, they pump less gas.

Tight supply has been exacerbated by Saudi Arabia’s and Kuwait’s adherence to OPEC’s oil output curbs since December 2008.

Kuwait is plugging the gap between supply and demand with imports of liquefied natural gas (LNG) while the world’s largest oil exporter Saudi Arabia has stepped up its exploration for gas after it completed a massive curde expansion program in 2009.